Abstract: | ![]() Model-fitting methods are described for estimating genetic and environmental contributions to the variation of behavioral traits. These methods are illustrated by application to data from recent large twin studies of neuroticism and extraversion and to summary data on IQ. Some possible environmental and genetic implications of the results are considered. The environmental implications of these analyses may be of even more interest to psychologists than the genetic ones. (PsycINFO Database Record (c) 2010 APA, all rights reserved) |